Aluminum diethylphosphinate crystal with low fine powder content, preparation method therefor and use thereof

Abstract

Disclosed are an aluminum diethylphosphinate crystal with a low fine powder content, a preparation method therefor and use thereof in flame retardance of glass fiber-reinforced engineering plastics. In the present invention, a phosphorus-containing aluminum salt complex is used as a seed crystal and is added in a crystallization process of preparing aluminum diethylphosphinate, such that the crystallization process can be effectively regulated and controlled, aluminum diethylphosphinate crystal particles with a low fine powder content, narrow distribution and a large particle size can be obtained, and the problems that the existing aluminum diethylphosphinate powder is prone to bridging, unsmooth feeding and the like can be solved. The present application is applicable to a processing technology of halogen-free flame retardant glass fiber-reinforced engineering plastics. The prepared aluminum diethylphosphinate includes a small amount of phosphorus-containing aluminum salt complex seed crystals, and the flame retardant property of the aluminum diethylphosphinate is not affected.

1 . A preparation method for an aluminum diethylphosphinate crystal with a low fine powder content, comprising: uniformly dispersing a phosphorus-containing aluminum salt complex, as a seed crystal, in an aqueous solution of soluble diethylphosphinate, adding a water-soluble aluminum salt solution containing a strong acid to carry out a reaction at 70-95° C., and after the reaction is completed, filtering, washing and drying a solid product to obtain the aluminum diethylphosphinate crystal with a low fine powder content;
 wherein the phosphorus-containing aluminum salt complex has a structure as shown in a formula (I) below: 
 
       
         
           
           
               
               
           
         
         in the formula (I), a, b, c, d and e are all molar ratios, a is 0.1-0.5, b is 0.5-0.9, c, d and e are 0-0.3, and a+b+c+d+e=1; R 1  and R 2  are independently selected from H and C 1 -C 6  alkyl, and when one of the R 1  and R 2  is ethyl, the other one is not ethyl and butyl; R 3  is C 1 -C 6  alkyl; 
         calculated with a theoretical mass of the aluminum diethylphosphinate product as 100%, an added amount of the phosphorus-containing aluminum salt complex is 0.01-10%; 
         and an average particle size (D50) of the phosphorus-containing aluminum salt complex satisfies 10 μm<D50<50 μm. 
       
     
     
         2 . The preparation method according to  claim 1 , wherein calculated with the theoretical mass of the aluminum diethylphosphinate product as 100%, an added amount of the phosphorus-containing aluminum salt complex is 0.1-5%. 
     
     
         3 . The preparation method according to  claim 1 , wherein the average particle size (D50) of the phosphorus-containing aluminum salt complex satisfies 20 μm<D50<40 μm. 
     
     
         4 . The preparation method according to  claim 1 , wherein the phosphorus-containing aluminum salt complex further comprises at least one of the following components (A)-(C):
 (A) one or more non-compound salts of ethylbutylphosphinate, dibutylphosphinate, ethylhexylphosphinate, butylhexylphosphinate and dihexylphosphinate;   (B) alkylphosphite;   (C) one or more of a sulfate, a chloride, a phosphate, a phosphite, a hypophosphite, a nitrate, an acetate, a nitrogen-containing compound, an iron-containing compound, a calcium-containing compound, a magnesium-containing compound, a titanium-containing compound, a sodium-containing compound and a potassium-containing compound.   
     
     
         5 . The preparation method according to  claim 1 , wherein the strong acid comprises at least one of sulfuric acid, nitric acid, hydrochloric acid and phosphoric acid;
 and calculated with the theoretical mass of the aluminum diethylphosphinate product as 100%, an added amount of the strong acid is 1-5%.   
     
     
         6 . The preparation method according to  claim 1 , wherein an aluminum salt in the water-soluble aluminum salt solution comprises at least one of aluminum sulfate, aluminum nitrate and aluminum chloride. 
     
     
         7 . The preparation method according to  claim 1 , wherein the prepared aluminum diethylphosphinate crystal with a low fine powder content comprises one or more mixture impurities of aluminum diethylphosphinate, aluminum ethylbutylphosphinate, aluminum dibutylphosphinate, aluminum ethylhexylphosphinate, aluminum butylhexylphosphinate and aluminum dihexylphosphinate. 
     
     
         8 . The preparation method according to  claim 1 , wherein the aluminum diethylphosphinate crystal with a low fine powder content comprises a phosphorus-containing aluminum salt complex seed crystal having an average particle size (D50) of 20 μm<D50<50 m and a bulk density of 500-700 g/L, and a content of a fine powder with a particle size of less than m is less than 10 wt %. 
     
     
         9 . An aluminum diethylphosphinate crystal with a low fine powder content prepared by the preparation method according to  claim 1 . 
     
     
         10 . A method of making glass fiber-reinforced engineering plastics with flame retardant property comprising the step of adding the aluminum diethylphosphinate crystal with a low fine powder content according to  claim 9  to the glass fiber-reinforced engineering plastics, wherein the glass fiber-reinforced engineering plastics adopt at least one of polyurethane, a thermoplastic elastomer, an epoxy resin, a thermosetting unsaturated polyester, nylon, a thermoplastic polyester and POK as a polymer matrix.